Strange throttle tip-in acceleration issue - can't diagnose

[fullboogie]

2008 V6 w/80k miles. I've been having an intermittent problem for some time that I just cannot fix. Truck will run fine for day or weeks at a time, then suddenly I get this problem - it can barely get out of its own way from a dead stop. It acts like its taking off in second or third gear, and accelerates very slowly. I can go WOT off the line and it just lugs, then at about 3,500 or 4,000 rpm begins acting normal. Next stop light it takes off fine. It is absolutely random and occurs whether the engine is hot or cold. This continues on and off throughout a drive cycle, and can last for a day or more. Gas mileage goes to shit during this time. Then it just magically disappears.

No codes or anything else I can see wrong in Torque with live monitoring
MAF has been cleaned 100 times with MAF cleaner
TB is clean as a whistle
Air filter is new
Plugs are properly gapped and new
No vacuum leaks
Did a tranny drain/refill and the fluid level is correct

I am stumped, but it's making me want to burn the truck down and bulldoze it into a hole and bury it. What am I missing???

 

[Atlanta_man]

....

 

[preacher35]

2008 V6 w/80k miles. I've been having an intermittent problem for some time that I just cannot fix. Truck will run fine for day or weeks at a time, then suddenly I get this problem - it can barely get out of its own way from a dead stop. It acts like its taking off in second or third gear, and accelerates very slowly. I can go WOT off the line and it just lugs, then at about 3,500 or 4,000 rpm begins acting normal. Next stop light it takes off fine. It is absolutely random and occurs whether the engine is hot or cold. This continues on and off throughout a drive cycle, and can last for a day or more. Gas mileage goes to shit during this time. Then it just magically disappears.

No codes or anything else I can see wrong in Torque with live monitoring
MAF has been cleaned 100 times with MAF cleaner
TB is clean as a whistle
Air filter is new
Plugs are properly gapped and new
No vacuum leaks
Did a tranny drain/refill and the fluid level is correct

I am stumped, but it's making me want to burn the truck down and bulldoze it into a hole and bury it. What am I missing???

[MENTION=107153]fullboogie[/MENTION]: Hey bud. Haven't spoken to you in a while. Sorry to hear about your Runner. I have seen something like this happen to a friend of mine. The behavior that your are describing coming from your Runner sounds identical. Is it possible that you have water in your fuel tank? It happens from time to time and can be very hard to diagnose. You will get completely random and inexplicable power loss with no indication on your gauges. The only other possibility that I can think of is that your throttle body may require a rebuild. Just something to think about. If you keep having the issue, I can recommend a local mechanic (who has a ton of experience with Toyotas) who has figured out some really mysterious crap that cause me to almost firebomb a couple of my vehicles and he is insanely reasonable on price. Good luck and keep me posted!!

 

[fullboogie]

OK, new development. For the first time ever, this morning Torque pulled an error code O2 sensor bank 4 sensor 4. What the hell does that mean? There's 2 banks and 2 sensors per bank. Any ideas?

Preacher man, please PM me your guys name and number. I need this fixed asap because I have a ten hour round trip in two weeks and I'm towing. Really need this fixed fast.

 

[RedSled]

Put a can of BG 44k in it and see if that helps.

 

[fullboogie]

Put a can of BG 44k in it and see if that helps.

LOL - the stuff they hawk on the Saturday morning mechanic shows? No thanks.

 

[preacher35]

PM sent.

 

[fullboogie]

Sure could use some additional input on this, guys. The problem seems to be getting worse. Is there any way to test fuel pressure on these V6's? I don't see a schraeder valve anywhere on the rail.

 

[RedSled]

LOL - the stuff they hawk on the Saturday morning mechanic shows? No thanks.

Excuse me, it's just an injector cleaner that removes carbon, and helps if you have moisture or water in the fuel.

 

[Greydog]

Check that your brake switch is not sticking. If the computer thinks your still on the brakes is can ack funny.

 

[BlackWorksInc]

OK, new development. For the first time ever, this morning Torque pulled an error code O2 sensor bank 4 sensor 4. What the hell does that mean? There's 2 banks and 2 sensors per bank. Any ideas?

Preacher man, please PM me your guys name and number. I need this fixed asap because I have a ten hour round trip in two weeks and I'm towing. Really need this fixed fast.

Your Torque app may need an update or is encountering a Toyota specific DTC; what is the DTC number? (i.e. P0303, P0456, ect.) An O2 Sensor most likely would not cause that severe a throttle issue, but it might be possible. I'd be more suspect on something a bit more fast acting such as an intermittent MAF failure. An odd DTC or impossible DTC is typically a scantool issue in either trying to interpret a non-OBDII Manufacturer specific DTC (I see this a lot on BMWs where they're OBDII DTCs are not the same as their BMW specific DTCs) or the scantool's software is not programmed correctly (usually an update fixes it.)

LOL - the stuff they hawk on the Saturday morning mechanic shows? No thanks.

Eh, we actually use the BG stuff at the dealer and the 44K actually seems to do a pretty good job (the BG EPR stuff we use is amazing, I honestly didn't believe how well it worked until we used it on a sludged a part's Tundra motor) at cleaning up the injectors and drying out the fuel. It's more like dumping Seafoam in your gas tank than say a professional injector bench cleaning (but both products do work decently, so it wouldn't hurt I suppose.)

 

[luke87gt]

Wondering if there have been any updates?